In forming a vertical type power device in a SiC substrate, it is desirable to thin the device and form a drain electrode in order to reduce a resistance in a thickness direction of the substrate. In forming the drain electrode, an ohmic electrode is formed to reduce a contact resistance between the SiC substrate and the drain electrode. Laser annealing can be applied to a method of making drain electrode as an ohmic electrode (see, for example, Patent Documents 1, 2)
Patent Document 1: JP-2008-135611A
Patent Document 2: JP-2009-509339A (corresponding to US 20070066039A)
In making a drain electrode as an ohmic electrode by laser annealing, a beam diameter of laser beam is smaller than an area of the drain electrode. For example, size of the drain electrode is 5 mm while the beam diameter of laser beam is 200 μm. Therefore, it may be necessary to move and scan the laser beam on an x-y plane, so that all the area of the drain electrode is irradiated with the laser beam. It is confirmed that when the SiC substrate is diced and divided into chips after the laser annealing, the chips break, that is, a chipping occurs.